DESCRIPTION

The
wcsnrtombs()
function is like the
wcsrtombs(3)
function,
except that the number of wide characters to be converted,
starting at
*src,
is limited to
nwc.

If
dest
is not NULL,
the
wcsnrtombs()
function converts
at most
nwc
wide characters from
the wide-character string
*src
to a multibyte string starting at
dest.
At most
len
bytes are written to
dest.
The shift state
*ps
is updated.
The conversion is effectively performed by repeatedly
calling
wcrtomb(dest, *src, ps),
as long as this call succeeds,
and then incrementing
dest
by the
number of bytes written and
*src
by one.
The conversion can stop for three reasons:

1.

A wide character has been encountered that can not be represented as a
multibyte sequence (according to the current locale).
In this case,
*src
is left pointing to the invalid wide character,
(size_t) -1
is returned,
and
errno
is set to
EILSEQ.

2.

nwc
wide characters have been
converted without encountering a null wide character (Laq\0aq),
or the length limit forces a stop.
In this case,
*src
is left pointing
to the next wide character to be converted, and the number of bytes written
to
dest
is returned.

3.

The wide-character string has been completely converted, including the
terminating null wide character (which has the side effect of bringing back
*ps
to the initial state).
In this case,
*src
is set to NULL, and the number
of bytes written to
dest,
excluding the terminating null byte (aq\0aq), is
returned.

If
dest
is NULL,
len
is ignored,
and the conversion proceeds as above,
except that the converted bytes are not written out to memory, and that
no destination length limit exists.

In both of the above cases,
if
ps
is NULL, a static anonymous
state known only to the
wcsnrtombs()
function is used instead.

The programmer must ensure that there is room for at least
len
bytes
at
dest.

RETURN VALUE

The
wcsnrtombs()
function returns
the number of bytes that make up the
converted part of multibyte sequence,
not including the terminating null byte.
If a wide character was encountered which
could not be converted,
(size_t) -1
is returned, and
errno
set to
EILSEQ.

ATTRIBUTES

For an explanation of the terms used in this section, see
attributes(7).

Interface

Attribute

Value

wcsnrtombs()

Thread safety

MT-Unsafe race:wcsnrtombs/!ps

CONFORMING TO

POSIX.1-2008.

NOTES

The behavior of
wcsnrtombs()
depends on the
LC_CTYPE
category of the
current locale.

Passing NULL as
ps
is not multithread safe.

SEE ALSO

COLOPHON

This page is part of release 4.13 of the Linux
man-pages
project.
A description of the project,
information about reporting bugs,
and the latest version of this page,
can be found at
https://www.kernel.org/doc/man-pages/.